Ronaldo wheeled away in celebration with hand cupped to his ear after smashing home Madrid's second after Pepe had headed Zinedine Zidane's men in front before half-time.
The three-time World Player of the Year added three more to surpass Telmo Zarra as the second-highest scorer in La Liga history with 252 goals in just 228 appearances.
And there was further good news for Real as Gareth Bale scored Madrid's seventh on his first appearance after six weeks out with a calf injury.
Ronaldo gets Madrid back to winning ways at Levante
Victory moved Real back to within nine points of leaders Barcelona, who travel to Eibar on Sunday.
"You know Cristiano, he is capable of scoring four goals and there are very few people capable of doing that. That is why he is unique," said Zidane.
"It is part of football that the fans whistle now and then.
"They are demanding fans, but at the same time they know their players well and always want more. That is good to help us improve and do more."
Advantage Barca as Real Madrid, Atletico held
There was little evidence that Ronaldo or Real were about to burst into life during a quiet first-half played out in front of a frustrated home crowd after last weekend's 1-0 defeat to Atletico in the Madrid derby.
Iago Aspas had a huge chance to put Celta in front when he headed against the bar before Keylor Navas smothered his follow-up effort from point-blank range.
Ronaldo didn't make his presence felt until 20 minutes in when his fierce strike from distance was beaten to safety by Ruben Blanco.
The Celta 'keeper also denied Isco and Casemiro, but the visitors were struggling to deal with cross balls and Pepe powered home the opener five minutes before the break from Isco's cross.
Ronaldo had controversially claimed Real would be top of the league if the rest of his teammates matched his exacting standards after the Atletico game.
And the Portuguese was met with a few whistles from the crowd early in the second half after losing possession twice in quick succession.
However, he responded instantly with a dipping strike from 25 yards that flew past Blanco.
Ronaldo immediately headed towards the stand behind the goal with his hand placed over his ear as a warning shot to his critics.
More was to come from Ronaldo as he then curled home a brilliant free-kick into the top corner.
Ronaldo hit the bar with another free-kick before Aspas capitalised on the huge amount of space in behind the Madrid defence to pull a goal back with a neat chip over Navas.
However, Madrid duly replied with a further three goals in 13 minutes.
Firstly, Ronaldo completed his 30th La Liga hat-trick with a tap in from Isco's unselfish low cross.
Bale then made his entrance with the Welsh star's return to fitness a huge boost for Zidane ahead of Madrid's Champions League last-16, second-leg clash with Roma on Tuesday.
Ronaldo headed home his fourth of the afternoon before substitute Jese Rodriguez smashed home Madrid's sixth after a fine solo run.
And Bale showed what Madrid were missing last week against Atletico when he drove at the Celta defence before firing in his 14th goal of the season off the post.
Madrid are now seven points clear of fourth-placed Villarreal after they succumbed to a first league defeat in 15 La Liga games, losing 1-0 at home to Las Palmas.
David Garcia's header just before half-time secured the Canary Islanders' third successive win to move four points clear of the relegation zone.
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